Same-sex marriage opponents asked him to step in Saturday, a day after the federal appeals court in San Francisco allowed same-sex marriages to go forward. The opponents said the appeals court had acted about three weeks too soon.

Under Supreme Court rules, decisions are not finalized for 25 days to allow requests for rehearings. But such rehearings are extremely rare.

Signs along the route read, ‘‘Thank you, Edie’’ — celebrating Windsor’s successful challenge of a provision of the Defense of Marriage Act that defined marriage as between a man and a woman.

‘‘If somebody had told me 15 years ago that I would be the marshal of New York City’s Gay Pride parade in 2013, at the age of 84, I wouldn’t have believed it.’’

Mayor Michael Bloomberg joined hundreds of bikers whose motorcycles roared to life at noon to kick off the celebration, a colorful cavalcade of activists and others who marched down Fifth Avenue 44 years after the city’s first pride march.

‘‘We’re Dykes on Bikes,’’ announced Marcia Jackson, of Burbank, Calif., a member of the lesbian motorcycle club who clutched the waist of Tyrone White on their motorcycle. Jackson grinned as she explained White’s connection to the sisterhood: He is undergoing a sex-change procedure.

Carl Siciliano, who heads the Ali Forney drop-in center for homeless gay youth in Harlem, said he is happy about the court decision. But he said the humanitarian fight is not over for lesbian, gay, bisexual, and transgendered youth.

‘‘Now that our adults have won this wonderful victory, it is time for us to begin to build a safety net for the more than 200,000 homeless LGBT youth who are stranded on America’s streets without shelter,’’ he said.

Windsor said she long enjoyed the parade with her late wife, Thea Spyer, whom she married in Canada as Spyer was dying in 2007. In 2009, she suffered a heart attack a month after Spyer’s death. While recovering, Windsor faced a hefty bill for inheritance taxes — more than $363,000, because Spyer was, legally, just a friend.

Sunday, Windsor was one of three grand marshals, joining musician and activist Harry Belafonte and Earl Fowlkes, head of the Center for Black Equity.